Electrically tuning the optical properties of materials has been extensively studied. Efforts to date have been focused on using liquid crystals, electrochromic materials, and phase change materials to achieve such tunability. These means of controlling optical properties have enabled numerous important applications, including optical filters and displays.
Electrochromic and phase change materials offer optical property modulation in all solid-state devices and are compatible with microelectronic processes. They can be used to make high-resolution displays and compact optical modulators. Electrochromic technology has achieved high contrast switching and low power consumption. However, conventional electrochromic devices require an ion storage layer, which increases the overall thickness of the gated layers and complicates the fabrication process.
Recently, phase change materials have been used to control optical properties electrically. They can achieve high localization and non-volatile switching, but nucleation-dominated crystallization limits their ability to achieve uniform reversible switching.